2319 - mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

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author	Kartik K. Agaram <vc@akkartik.com>	2015-10-29 16:43:50 -0700
committer	Kartik K. Agaram <vc@akkartik.com>	2015-10-29 16:43:50 -0700
commit	f8badcdc0ce3b6d7dba5932f85f4bc529bcab128 (patch)
tree	484cf47dfe7721094abd52d5c1428e68df9e48a6 /tangle.mu
parent	02feee3c8de62fda69216993639d5db2684b1f45 (diff)
download	mu-f8badcdc0ce3b6d7dba5932f85f4bc529bcab128.tar.gz

2319

Diffstat (limited to 'tangle.mu')

0 files changed, 0 insertions, 0 deletions

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Mu - subx/x.subx</title> <meta name="Generator" content="Vim/7.4"> <meta name="plugin-version" content="vim7.4_v2"> <meta name="syntax" content="none"> <meta name="settings" content="number_lines,use_css,pre_wrap,no_foldcolumn,expand_tabs,line_ids,prevent_copy="> <meta name="colorscheme" content="minimal"> <style type="text/css">  </style> <script type='text/javascript'>  </script> </head> <body onload='JumpToLine();'> <pre id='vimCodeElement'> 1 ## compute the factorial of 5, and return the result in the exit code 2 # 3 # To run: 4 # $ subx translate ex7.subx ex7 5 # $ subx run ex7 6 # Expected result: 7 # $ echo $? 8 # 120 9 10 == 0x08048054 # code segment, after leaving room for ELF header 11 # instruction effective address operand displacement immediate 12 # op subop mod rm32 base index scale r32 13 # 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes 14 15 # main: 16 # prepare to make a call 17 55/push . . . . . . . . # push EBP 18 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP 19 # factorial(5) 20 68/push . . . . . . . 5/imm32 # push 5 21 e8/call . . . . . . factorial/disp32 22 # discard arg 23 5a/pop . . . . . . . . # pop into EDX 24 # clean up after call 25 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP 26 5d/pop . . . . . . . . # pop to EBP 27 28 # exit(EAX) 29 89/copy 3/mod/direct 3/rm32/EBX . . . 0/r32/EAX . . # copy EAX to EBX 30 b8/copy . . . . . . . 1/imm32 # copy 1 to EAX 31 cd/syscall . . . . . . . 0x80/imm8 # int 80h 32 33 # factorial(n) 34 factorial: 35 # initialize n 36 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 2/r32/EDX 4/disp8 . # copy *(ESP+4) to EDX 37 # initialize EAX to 1 (base case) 38 b8/copy . . . . . . . 1/imm32 # copy 1 to EAX 39 # if (n <= 1) jump exit 40 81 7/subop/compare 3/mod/direct 2/rm32/EDX . . . . . 1/imm32 # compare EDX with 1 41 7e/jump-if . . . . . . factorial:exit/disp8 # jump if <= to exit 42 # EBX: n-1 43 89/copy 3/mod/direct 3/rm32/EBX . . . 2/r32/EDX . . # copy EDX to EBX 44 81 5/subop/subtract 3/mod/direct 3/rm32/EBX . . . . . 1/imm32 # subtract 1 from EBX 45 # prepare call 46 55/push . . . . . . . . # push EBP 47 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP 48 # EAX: factorial(n-1) 49 53/push . . . . . . . . # push EBX 50 e8/call . . . . . . factorial/disp32 51 # discard arg 52 5e/pop . . . . . . . . # pop into ESI 53 # clean up after call 54 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP 55 5d/pop . . . . . . . . # pop to EBP 56 # refresh n 57 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 2/r32/EDX 4/disp8 . # copy *(ESP+4) to EDX 58 # return n * factorial(n-1) 59 0f af/multiply 3/mod/direct 2/rm32/EDX . . . 0/r32/EAX . . # multiply EDX (n) into EAX (factorial(n-1)) 60 # TODO: check for overflow 61 factorial:exit: 62 c3/return 63 64 # vim:ft=subx:nowrap:so=0 </pre> </body> </html>


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